Acute effect of static stretching on passive stiffness of the human gastrocnemius fascicle measured by ultrasound shear wave elastography
Acute effect of static stretching on passive stiffness of the human gastrocnemius fascicle measured by ultrasound shear wave elastography
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DOI：
10.1007/s00421-017-3550-z
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发表时间：
2017-03-01
影响因子：
3
通讯作者：
Miyamoto, Naokazu
中科院分区：
文献类型：
--
作者：
Hirata, Kosuke;Kanehisa, Hiroaki;Miyamoto, Naokazu
被动肌肉僵硬和肌肉结构在给定的关节角度，以及松弛的角度的肌肉已被证明改变后，急性回合的拉伸。然而，目前尚不清楚的是，在给定的肌束长度处，被动肌肉僵硬度在拉伸后是否会降低。我们的目的是利用超声剪切波弹性成像来阐明静态拉伸对被动肌束刚度的急性影响。测定了14例健康男性静态拉伸前后5min时腓骨内侧肌剪切模量、肌束长度、松弛角以及被动背屈时的被动足底屈曲力矩。拉伸后，被动扭矩在活动范围（ROM）的50%显著降低。在被动背屈时，给定束长度的剪切模量在束长度变化的80%时显著降低。在ROM中部观察到MG松弛角，拉伸后明显向更背屈的位置移动。本研究显示静态拉伸对被动肌束刚度的显著有效性。此外，本研究结果表明，在被动背屈过程中，松弛角的变化和被动肌束刚度的降低共同导致了被动扭矩-关节角关系的变化。值得注意的是，在ROM的后期，被动筋膜刚度的降低对被动扭矩的减少的贡献是实质性的。
Passive muscle stiffness and muscle architecture at a given joint angle, as well as slack angle of the muscle have been shown to change after an acute bout of stretching. However, it remains unclear whether passive muscle stiffness at a given fascicle length is reduced after stretching. We aimed to elucidate the acute effect of static stretching on the passive fascicle stiffness using ultrasound shear wave elastography.Shear modulus, fascicle length, and slack angle of the medial gastrocnemius (MG) as well as passive plantar flexion torque during passive dorsiflexion were measured before and after a 5-min static stretching in 14 healthy males.After stretching, passive torques were significantly reduced at > 50% of range of motion (ROM). Shear modulus at a given fascicle length was significantly reduced at > 80% of the change in fascicle length during passive dorsiflexion. Slack angle of MG was observed at the middle part of ROM and significantly shifted toward more dorsiflexed position after stretching.The present study showed the significant effectiveness of static stretching on the passive fascicle stiffness. Furthermore, the present results suggest that both the shift in slack angle and the reduction in passive fascicle stiffness contribute to produce the change in passive torque-joint angle relationship during passive dorsiflexion. Notably, the contribution of the reduced passive fascicle stiffness to the decrease in passive torque is substantial over the latter part of ROM.